The invention relates to a linear guide arrangement comprising a guide rail having an axis and at least one guide carriage, movable on this guide rail in the direction of the axis, which runs on the guide rail with intermediacy of at least one endless rolling-element circuit, this rolling-element circuit consisting of a bearing row of rolling elements in simultaneous engagement with a bearing rolling-element raceway of the guide rail and a bearing rolling-element raceway of the guide carriage, a returning row of rolling elements in a rolling-element return guide of the guide carriage and curved rows of rolling elements which connect the bearing row of rolling elements and the returning row of rolling elements together at their ends and run in curved rolling-element guides of the guide carriage, where the guide carriage is designed with a guide carriage housing and with a carriage member made separately from the guide carriage housing and accommodated within the guide carriage housing, where in addition, the guide carriage housing comprises at least one side panel adjacent to the rolling-element circuit and substantially parallel to the axial direction and additionally comprises at least one end plate adjacent to one of the curved rows of rolling elements and substantially orthogonal to the axial direction, while in addition, the bearing row of rolling elements runs on the carriage member.
In a linear guide arrangement disclosed in EP-0,474,948, a carriage member is surrounded by a guide carriage housing. The guide carriage housing has the shape of a rectangular frame with side panels that run parallel to the axis of the guide rail and with end plates lying orthogonal to the axis of the guide rail. Radially outer curved guide surfaces of the curved rolling-element guides and rolling-element guide surfaces of the rolling-element return guides connecting to the latter are formed in the side panels. On the carriage member are formed guide strips, which, upon insertion of the carriage member into the guide carriage housing, extend into the region of the radially outer curved guide surfaces and the return guide surfaces of the side panels and thus supplement the curved rolling-element guides and the rolling-element return guides.
In this embodiment, the guide strips of the carriage member, as a rule made of steel, are necessarily shorter in the direction of the axis of the guide rail than the distance between the faces of the carriage member resting on the end plates. This means that costly machining of the carriage member is necessary in order to adjust it to the guide carriage housing so that it can be inserted into the housing in the correct position. Thus, it is not possible merely to obtain the carriage member of drawn material simply by cutting off a length of material; nor is it sufficient to regrind cut-off pieces of the length of material producing the carriage member by simple grinding processes for the purpose of increasing accuracy. Rather, milling processes are required in order to work the ribs out of a cut-off piece of a length of material. According to a first embodiment of EP-0,474,948 A1 (see FIG. 2 therein), radially inner guide faces of the curved rolling-element guides are formed at the ends of the ribs. This means that particularly costly machining of the ribs is required in order to obtain the radially inner guide faces of the curved rolling-element guides on them. According to a modified embodiment (see FIG. 5 of EP-0,474,948 A1), the radially inner curved guide surfaces of the curved rolling-element guides are formed on reversing pieces, which in turn are formed in one piece on the side panels of the guide carriage housing. It is true that this facilitates production of the radially inner curved guide surfaces if these curved guide surfaces become parts of the guide carriage housing, which can be made, for example, as an injection-molded part or as a cast part of synthetic material or metal. However, this does not solve the problem of costly production of the carriage member because the ribs must still be shorter than the longitudinal extension of the guide carriage member in the direction of the guide rail axis, with the consequence that transverse milling machining of the guide carriage member is necessary in any case.
EP-0,494,682 discloses a linear guide unit wherein reversing plates for radially outer curved guide surfaces of the curved rolling-member guides are mounted on a carriage member of constant profile on its entire length and hence relatively easy to produce. There, the two plates, which are alike, are in each instance joined in one piece with a side panel. Each of these side panels is provided at its end distant from the associated reversing plate with a snap hook, which upon assembly snaps into a hook recess of the other reversing plate in each instance. Positioning of the reversing plates on the carriage member in transverse direction to the guide rail axis is effected by positioning tongues, which engage in positioning grooves on the carriage member running parallel to the axis. Production of the reversing plates with the side panel formed on in each instance and the hook recess formed on in each instance is very costly in terms of shaping technique, even when it is intended to produce these reversing plates by casting or injection molding.
A sealing frame, which has longitudinal sealing lips in position parallel to the guide rail axis and end sealing plates for sealing engagement with the guide rail profile, is provided for sealing off the rolling-element circuit and the lubricant supplied to it. However, this sealing frame does not serve to hold the reversing plates together, but--on the contrary--is supported by the reversing plates held together by the side panels.
Concerning the prior art with regard to linear guide units, reference is additionally made to the following printed sources:
U.S. Pat. No.4,505,522 PA1 Prospectus, THK Bearings of the THK Company Ltd., publication number SA 600,310 PA1 Prospectus, THK LM System Linearfuhrungen [Linear Guides], catalog number 100-1 AG PA1 Prospectus, INA Miniaturkugelumlauf, Einheit KUME [Miniature ball circuit, Unit KUME], prospectus number T 452 D -03/92 PA1 DE 3,313,575 A1 PA1 DE 3,152,257 C2 PA1 EP-0,474,948 A1 PA1 EP 379,827 A1 PA1 DE 3,128,628 A1 PA1 U.S. Pat. No. 4,637,739 PA1 DE 3,607,592 C2 PA1 EP-0,494,682 A2 PA1 EP-0,608,832 A2 PA1 DE 3,416,207 C2 PA1 Prospectus, Franke & Heydrich KG, Franke-Linearfuhrungen mit neuem Kugelumlaufelement KU [Franke linear guides with new ball circuit element KU] PA1 DE-A-2,027,338
Prospectus, Franke & Heydrich, Einfache und doppelkugel-fuhrungen [Single and double ball guides]